Weather radio receivers for use with the National Oceanic and Atmospheric Administration Weather Radio (NWR) service are widely available and incorporate various features according to cost and manufacturer. The most basic receiver feature consists of providing an emergency alert notification in response to a NWR broadcast describing an event that threatens life or property.
The National Weather Service (NWS) uses an NWR-Specific Area Message Encoding (NWR-SAME) scheme. By placing encoded information at the beginning and end of each emergency broadcast, the NWR-SAME scheme permits greater control of transmitters, receivers, and other broadcasting equipment within a specific geographic region. The encoded information is transmitted on NWR radio channels using audio frequency shift keying (AFSK) and contains information describing the emergency and the NWR-SAME emergency alert broadcast. Aspects of this information may include, for example, the emergency type, the geographic area affected, the expected duration of time for which the information contained in the emergency alert broadcast is valid, the date and time of the broadcast, and the identify of the broadcast originator. A weather radio receiver capable of interpreting this information may be programmed to provide an emergency alert notification in response to receiving a NWR-SAME broadcast only if user-defined emergency alert preferences such as, for example, the emergency type and the geographic area affected, are satisfied.